class RSpec::Core::SharedExampleGroupModule

group.
eval’d when the ‘SharedExampleGroupModule` instance is included in an example
The functionality is defined by the provided block, which is lazily
Represents some functionality that is shared with multiple example groups.

def included(klass)

including example group.
Our definition evaluates the shared group block in the context of the
Ruby callback for when a module is included in another module is class. 
def included(klass)
  inclusion_line = klass.metadata[:location]
  SharedExampleGroupInclusionStackFrame.with_frame(@description, inclusion_line) do
    klass.class_exec(&@definition)
  end
end

def initialize(description, definition) 

def initialize(description, definition)
  @description = description
  @definition  = definition
end

def inspect

Provides a human-readable representation of this module. 
def inspect
  "#<#{self.class.name} #{@description.inspect}>"
end